In a mixing bowl, whisk together the milk, apple cider vinegar, egg yolks, 6 tablespoons melted unsalted butter, vanilla and 1 tbsp sugar.
Add the flour, cocoa powder, baking powder and salt and stir until just combined. It’s OK if the batter is a little lumpy.
Whip the egg whites stiff in a clean and dry mixing bowl till stiff. TIP: Turn the bowl upside down, if it doesn’t fall off, the egg whites are whipped right.
Gently fold in the whites into the batter. Allow the batter to sit 5-10 minutes.
Now heat the waffle iron, brush some oil / butter on it and pour 1 cup of batter in to the pan. Close the lid carefully and let it cook it for 3-4 mins per side. or as per your waffle makers instructions.
For the churro rub
Brush the waffles liberally with melted butter. Now rub the cinnamon+sugar mixture well all over the waffles, drizzle with mocha sauce, garnish and enjoy!!
For the mocha sauce
Mix everything in a sauce pan. Bring to a boil and mix well. Let it simmer for 10 mins till thick. You can add a pinch of seasalt or nutmeg too.